#include <iostream>
using std::cout;
using std::endl;

void swap3(int &x, int &y){//引用传递，不复制
    int temp = x;
    x = y;
    y = temp;
}

void test0(){
    int a = 10;
    int b = 20;
    swap3(a, b);

    printf("a = %d, b = %d\n", a, b);
}

int main(void){
    test0();
    return 0;
}

